1. Field of the Invention
The present invention relates to a technology for assisting or guiding a cogenerator operation method, so that necessary quantities of electric power or steam for use in factories or other buildings can be optimally generated in view of particular purposes, such as for the minimization of cost or carbon dioxide emissions. The invention also relates to an energy management system for assisting energy cutting measures in factories or other buildings, such as by assisting or guiding certain air conditioning settings. Beyond energy applications, the invention can also be used in assisting the operator of a system in which a final plan is decided upon based on appropriate results provided by computer and those provided by human (operator) senses. Furthermore, the invention can be applied to systems in which the appropriateness of results (processes) of human decisions is evaluated for the purpose of improving humanity's decision-making abilities.
2. Background Art
Due to problems such as global warming, finding methods of saving energy is now a pressing concern for humanity. In the 3rd Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (in Kyoto), concrete targets were set for reducing amounts of carbon dioxide emissions. In Japan, an Energy Conservation Law has been made, and large factories now employ certified energy conservation specialists. As a means of conserving energy, cogeneration technology is gaining attention. Cogeneration generates electric power/steam (heat) from fuels and utilizes both. A cogeneration system is comprised of an intricate combination (flow of energy) of elements such as a gas turbine, steam turbine, boiler, gas engine, micro-gas turbine, and heat regenerator. The electric or steam (thermal) power demand at operation target factories or buildings varies continuously. Thus, it is difficult for operators to calculate or plan how cogenerator operating equipment, including gas turbines, steam turbines, boilers, gas engines and micro-gas turbines, should be operated in order to meet the changing energy demand every day or for each instance in an energy- and cost-efficient manner. Accordingly, there is a need for a cogenerator operation assisting system that can predict electric power/steam demand at factories or other buildings and determine the most energy- or cost-efficient method of operating gas or steam turbines depending on the predicted electric power/steam demand, thus providing operation guidance.
In the prior art, a system has been proposed that predicts the electric power/steam demand at an operation target facility for a given day on an hourly basis based on weather conditions and schedule. The system then determines a cost-minimizing method of operating the cogenerator for supplying the necessary electric power/steam, thus providing guidance to the operator.
JP Patent Publication (Kokai) No. 2000-274308 A discloses a method of determining a cost-minimizing power supply (operation) method based on a combination of electricity purchase and cogeneration. JP Patent Publication (Kokai) No. 9-285010 A (1997) describes a method of predicting demand based on demand prediction results provided by a plurality of demand prediction means.
Prediction of electric power/steam demand on a continuous basis is required, because electric power cannot be stored. Machine-based predictions, however, are often inaccurate. Various counter-measures have been proposed, such as disclosed in the above-mentioned publication JP Kokai No. 9-285010, and yet the results are not accurate enough. As a result, operators, unable to put faith in demand predictions on the basis of which they are supposed to plan an optimum operation method, begin to rely on educated guesses and disregard the use of machines even for the calculation or planning of a cost- and energy-minimizing method of supplying energy, which they are best at. This has not necessarily resulted in energy- and cost-saving operations and, moreover, often discouraged the operators' enthusiasm for the cause of energy conservation, for they have no idea how much they are contributing to energy-saving efforts.